Links between ice dynamics, subglacial hydrology, and sediment flux from glaciers under increased melt conditions

Warming-driven melt impacts the landscape in glacierized catchments by altering bedrock erosion and the processes that mobilize subglacial sediment, affecting the delivery of sediment to downstream systems. Here, we synthesize insights from sediment export observations, together with numerical modeling experiments that evaluate ice motion, subglacial water flow, and sediment transport as they respond to change hydro-climatic conditions. The synthesis highlights timescale-dependent controls on sediment production, access, and mobilisation processes. During millennial-scale glacial retreat, steeper ice surfaces and warmer basal conditions increase glacier sliding, likely raising potential sediment production rates through bedrock abrasion. At decadal to annual scales, higher melt elevations allow water to access previously stored subglacial material further upglacier from the ice margin, so that sediment export may increase even as ice thins and sediment production rates fall. At event scales, such as during rapid discharge pulses from precipitation events, heatwaves, or floods, can strongly amplify transport capacity because subglacial conduits adjust slowly, causing intense variations in sediment transport capacity. These interacting processes imply that erosion rate estimates depend strongly on the duration of their observational period, potentially biasing observed rates toward pulses or hiatuses. Lastly, we discuss topics where the impact of greater hydro-climatic conditions on glacier erosion and sediment export is less well understood. These include the transport of sediment from ice sheets, along with the export of large sediment sizes as bedload. Finally, we outline how emerging in-situ sensing, novel geochronology, and next-generation models can better link climate forcing to sediment flux across timescales.